Vacuum-assisted headspace solid-phase microextraction and gas chromatography coupled to mass spectrometry applied to source rock analysis

Vacuum-assisted headspace solid phase microextraction (Vac-HSSPME) with high temperature of extraction was used for source-rock analysis. Optimization of extraction conditions was performed by Doehlert experimental design (DD) in gas chromatography coupled to mass spectrometer detector (GC–MS). Samples from the same oil well were mixed to obtain a mean stratigraphic characteristic for extraction optimization. Source-rock samples were analyzed in the DD optimal conditions and the proposed Vac-HSSPME+GC–MS method was compared to the classical procedure (SARA). The identification of important biomarkers like steranes and pentacyclic terpanes was possible. Fingerprint comparison between both methods shows similarity for steranes profile of overall chromatographic signal and compounds distribution. Also, it was possible to assess theoretical kinetic considerations for the system, as it differs from most conditions reported in literature. Furthermore, no organic solvent was used during the extraction or analysis with Vac-HSSPME. Classifying the procedure as a green methodology, while being faster and cheaper for oil bearing source-rock analyses.